You forgot an extremely common one;

Impersonation
This trick typically works when a new user has the same or a very similar username to an established member. Often these users will wait until the real member and the mark (target) are engaged in a conversation, then throughout this conversation they will message the mark while impersonating the established member for the purposes of scamming them. This is particularly common on Telegram, where people will have the same or very similar descriptions in their profile, but will usually lack a username, or have a very similar username to a person of status, e.g. an admin or renowned bitcointalk individual. This trick most commonly targets those who are unfamiliar with Bitcointalk, since the main distinguishing factor is the activity, post count and merit, which are things newbies might fail to check, instead relying solely on the username.